/* Academic Professional Website - Design System */

/* Design Tokens */
:root {
  /* Colors */
  --color-primary: #0E419C;
  --color-primary-dark: #0A2F70;
  --color-text: #000000;
  --color-text-secondary: #000000;
  --color-background: #ffffff;
  --color-border: rgba(14, 65, 156, 0.1);
  --color-border-light: rgba(14, 65, 156, 0.05);

  /* Typography Scale */
  --font-size-xs: 12px;
  --font-size-sm: 14px;
  --font-size-base: 15px;
  --font-size-lg: 18px;
  --font-size-xl: 24px;
  --font-size-xxl: 32px;

  /* Font Weights */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Line Heights */
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.6;

  /* Spacing Scale */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 32px;
  --space-xl: 48px;
  --space-xxl: 64px;

  /* Layout */
  --container-max-width: 1200px;
  --border-radius: 8px;
  --transition: all 0.2s ease;
  --transition-smooth: all 0.3s ease;
}

/* Base Styles */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
  background: var(--color-background);
  font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-relaxed);
  color: var(--color-text);
  letter-spacing: 0.01em;
  padding-top: var(--space-lg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: 'Roboto', sans-serif;
  color: var(--color-primary);
  margin: 0 0 var(--space-sm) 0;
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-tight);
  letter-spacing: -0.01em;
}

h1 {
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-xxl);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-sm);
}

h3 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-xs);
  text-decoration: none;
}

h4, h5, h6 {
  font-size: var(--font-size-base);
  margin-bottom: var(--space-xs);
}

p {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  margin: 0 0 var(--space-xs) 0;
  color: var(--color-text);
}

/* Links */
a {
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--color-primary);
}

.main-content a {
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition);
  position: relative;
}

.main-content a::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  width: 0;
  height: 1px;
  background: rgba(14, 65, 156, 0.6);
  transition: var(--transition-smooth);
  transform: translateX(-50%);
}

.main-content a:hover {
  color: var(--color-primary);
}

.main-content a:hover::after {
  width: 100%;
}

/* Layout */
.main-content {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: var(--space-sm) var(--space-sm) var(--space-xxl) var(--space-sm);
  min-height: calc(100vh - 140px);
}

/* Navigation */
.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: transparent;
  padding: 1px var(--space-md);
  margin-bottom: var(--space-lg);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  width: 100%;
  z-index: 9999;
  will-change: background, backdrop-filter;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.navbar-title {
  font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  letter-spacing: 0.5px;
  text-decoration: none;
  transition: var(--transition-smooth);
  position: relative;
  padding: 4px var(--space-xs);
}

.navbar-title:hover {
  color: var(--color-primary);
}

.navbar-nav {
  display: flex;
  align-items: center;
  font-size: var(--font-size-base);
  position: relative;
}

.nav-link {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  text-decoration: none;
  margin: 0 3px;
  padding: var(--space-xs) 12px;
  border-radius: 4px;
  transition: var(--transition-smooth);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  width: 0;
  height: 1px;
  background: rgba(14, 65, 156, 0.6);
  transition: var(--transition-smooth);
  transform: translateX(-50%);
}

.nav-link:hover {
  color: var(--color-primary);
}

.nav-link:hover::after {
  width: 100%;
}

.nav-link.active {
  color: var(--color-primary);
  font-weight: var(--font-weight-bold);
}

.nav-link.active::after {
  width: 100%;
  height: 1px;
  background: rgba(14, 65, 156, 0.8);
}

.nav-separator {
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-base);
  margin: 0 4px;
}

/* Navigation Links Container */
.nav-links {
  display: flex;
  align-items: center;
  gap: 0;
}

/* Mobile Menu */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  justify-content: space-around;
  width: var(--space-lg);
  height: var(--space-lg);
  padding: 6px;
  transition: var(--transition);
  border-radius: 4px;
  will-change: background;
}

.hamburger-line {
  width: 20px;
  height: 2px;
  background: var(--color-primary);
  transition: all 0.3s ease-in-out;
  transform-origin: center;
  border-radius: 1px;
  will-change: transform, opacity;
}

.mobile-menu-toggle.active .hamburger-line:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-toggle.active .hamburger-line:nth-child(2) {
  opacity: 0;
  transform: scale(0);
}

.mobile-menu-toggle.active .hamburger-line:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

.mobile-menu-toggle:hover {
  background: rgba(14, 65, 156, 0.05);
}

.mobile-menu-toggle:hover .hamburger-line {
  background: var(--color-primary-dark);
}

/* Conference Table Styles */
.table-container {
  overflow-x: auto;
  margin: var(--space-md) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.conferences-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
  background: var(--color-background);
  table-layout: fixed;
}

.conferences-table th {
  background: rgba(14, 65, 156, 0.05);
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
  padding: var(--space-xs);
  text-align: left;
  border-bottom: 2px solid var(--color-border);
  position: relative;
}

.conferences-table td {
  padding: var(--space-xs);
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

/* Column width control */
.conferences-table th:nth-child(1),
.conferences-table td:nth-child(1) {
  width: 35%; /* Conference Name */
}

.conferences-table th:nth-child(2),
.conferences-table td:nth-child(2) {
  width: 17%; /* Deadline */
}

.conferences-table th:nth-child(3),
.conferences-table td:nth-child(3) {
  width: 18%; /* Conference Date */
}

.conferences-table th:nth-child(4),
.conferences-table td:nth-child(4) {
  width: 12%; /* Continent */
}

.conferences-table th:nth-child(5),
.conferences-table td:nth-child(5) {
  width: 18%; /* Location */
  max-width: 0; /* Force truncation */
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.conferences-table tr:hover {
  background: rgba(14, 65, 156, 0.02);
}

.conference-link {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: var(--transition);
}

.conference-link:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* Page header and footer */
.page-header {
  text-align: center;
  margin-bottom: var(--space-lg);
  padding: var(--space-md) 0;
}

.page-header h1 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  margin: 0;
}

.page-description {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  margin: var(--space-sm) 0 0 0;
  font-weight: var(--font-weight-normal);
}

/* Page footer */
.page-footer {
  text-align: center;
  margin-top: var(--space-xl);
}

.page-footer p {
  color: var(--color-text-light);
  font-size: calc(var(--font-size-base) * 0.9);
  margin: 0;
}

.author-link {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: var(--transition);
}

.author-link:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* Responsive Design - Mobile First */
@media (max-width: 991px) {
  body {
    padding-top: var(--space-lg);
  }

  .navbar {
    padding: 1px var(--space-sm);
  }

  .navbar-brand {
    gap: var(--space-sm);
  }

  .navbar-title {
    font-size: var(--font-size-lg);
  }

  .navbar-nav {
    font-size: var(--font-size-base);
  }

  .nav-link {
    font-size: var(--font-size-sm);
    padding: 6px 10px;
    margin: 0 2px;
    min-height: 40px;
  }

  .nav-separator {
    margin: 0 2px;
    font-size: var(--font-size-sm);
  }

  .main-content {
    padding: var(--space-xl) var(--space-sm) var(--space-sm) var(--space-sm);
  }
}

@media (max-width: 767px) {
  body {
    padding-top: var(--space-lg);
  }

  .navbar {
    padding: 1px var(--space-sm);
  }

  .navbar-brand {
    gap: var(--space-xs);
  }

  .navbar-title {
    font-size: var(--font-size-base);
  }

  .navbar-nav {
    font-size: var(--font-size-sm);
  }

  .mobile-menu-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: calc(100% + var(--space-xs));
    right: 0;
    background: rgba(255,255,255,0.98);
    border-radius: var(--space-xs);
    padding: var(--space-xs) 6px;
    flex-direction: column;
    align-items: stretch;
    z-index: 1000;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1), 0 2px 4px rgba(0, 0, 0, 0.06);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links a {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    padding: var(--space-xs) var(--space-sm);
    margin: 2px 5px;
    border-radius: var(--space-xs);
    height: 36px;
    min-width: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    transition: var(--transition);
  }

  .nav-links a:hover {
    background: rgba(255,255,255,0.2);
  }

  .nav-separator {
    display: none;
  }

  .main-content {
    padding: var(--space-xl) var(--space-sm) var(--space-sm) var(--space-sm);
  }

  /* Responsive table */
  .conferences-table {
    font-size: var(--font-size-xs);
  }

  .conferences-table th,
  .conferences-table td {
    padding: 4px var(--space-xs);
  }

  /* Adjust column widths for mobile */
  .conferences-table th:nth-child(1),
  .conferences-table td:nth-child(1) {
    width: 30%; /* Conference Name - slightly smaller */
  }

  .conferences-table th:nth-child(2),
  .conferences-table td:nth-child(2) {
    width: 23%; /* Deadline */
  }

  .conferences-table th:nth-child(3),
  .conferences-table td:nth-child(3) {
    width: 22%; /* Conference Date */
  }

  .conferences-table th:nth-child(4),
  .conferences-table td:nth-child(4) {
    width: 10%; /* Continent - smaller */
  }

  .conferences-table th:nth-child(5),
  .conferences-table td:nth-child(5) {
    width: 15%; /* Location - more aggressive truncation */
  }
}

@media (max-width: 575px) {
  body {
    padding-top: var(--space-lg);
  }

  .navbar {
    padding: 1px var(--space-xs);
  }

  .navbar-brand {
    gap: var(--space-xs);
  }

  .navbar-title {
    font-size: var(--font-size-sm);
  }

  .nav-links {
    border-radius: var(--space-xs);
    padding: var(--space-xs) 4px;
  }

  .nav-links a {
    font-size: var(--font-size-sm);
    padding: var(--space-xs) var(--space-xs);
    margin: 1px 4px;
    border-radius: var(--space-xs);
    height: var(--space-lg);
    min-width: 85px;
  }

  .main-content {
    padding: var(--space-xl) var(--space-xs) var(--space-xs) var(--space-xs);
  }
}

@media (max-width: 400px) {
  body {
    padding-top: var(--space-lg);
  }

  .navbar {
    padding: 1px var(--space-xs);
  }

  .navbar-brand {
    gap: var(--space-xs);
  }

  .navbar-title {
    font-size: var(--font-size-xs);
  }

  .main-content {
    padding: var(--space-xl) var(--space-xs) var(--space-xs) var(--space-xs);
  }
}

/* Touch Device Optimizations */
@media (hover: none) and (pointer: coarse) {
  .nav-link {
    min-height: 44px;
    min-width: 44px;
  }
}

/* Print Styles */
@media print {
  .navbar {
    display: none;
  }

  body {
    padding-top: 0;
  }
}